| <html> |
| <title>Xalan SQL Extension</title> |
| <body> |
| <p><em>**Experimental**</em> Provides extension functions for connecting to a JDBC data source, executing a query, |
| and working incrementally through "streamable" result set.<p> |
| <p><em>The SQL extension use of a single row-set node to incrementally return a query result set is experimental. Keep in mind that you |
| can only access row elements one at a time moving forward through the result set. The use of XPath expressions in your stylesheet, for |
| example, that attempt to return nodes from the result set in any other manner may produce unpredictable results.</em></p> |
| <p>XConnection provides three extension functions that you can use in your stylesheet.</p> |
| <ol> |
| <li><p>new() -- Use one of the XConnection constructors to connect to a data source, and return an XConnection |
| object.</p></li> |
| <li><p>query() -- Use the XConnection object query() method to return a "streamable" result set in the form of a row-set |
| node. Work your way through the row-set one row at a time. The same row element is used over and over again, so you can |
| begin "transforming" the row-set before the entire result set has been returned.</p></li> |
| <li>close() -- Use the XConnection object close() method to terminate the connection.</li> |
| </ol> |
| <p>The query() extension function returns a Document node that contains (as needed) an array of column-header elements, |
| a single row element that is used repeatedly, and an array of col elements. Each column-header element (one per column in the |
| row-set) contains an attribute (ColumnAttribute) for each of the column descriptors in the ResultSetMetaData object. |
| Each col element contains a text node with a textual representation of the value for that column in the current row.</p> |
| <h2>Example</h2> |
| <p>This example displays the result set from a table in a sample InstantDB database.</p> |
| <pre><?xml version="1.0"?> |
| <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" |
| version="1.0" |
| xmlns:sql="org.apache.xalan.lib.sql.XConnection" |
| extension-element-prefixes="sql"> |
| <xsl:output method="html" indent="yes"/> |
| <xsl:param name="query" select="'SELECT * FROM import1'"/> |
| |
| <xsl:template match="/"> |
| <!-- 1. Make the connection --> |
| <xsl:variable name="products" |
| select="sql:new('org.enhydra.instantdb.jdbc.idbDriver', |
| 'jdbc:idb:D:\instantdb\Examples\sample.prp')"/> |
| <HTML> |
| <HEAD> |
| </HEAD> |
| <BODY> |
| <TABLE border="1"> |
| <!--2. Execute the query --> |
| <xsl:variable name="table" select='sql:query($products, $query)'/> |
| <TR> |
| <!-- Get column-label attribute from each column-header--> |
| <xsl:for-each select="$table/row-set/column-header"> |
| <TH><xsl:value-of select="@column-label"/></TH> |
| </xsl:for-each> |
| </TR> |
| <xsl:apply-templates select="$table/row-set/row"/> |
| <xsl:text>&#10;</xsl:text> |
| </TABLE> |
| </BODY> |
| </HTML> |
| <!-- 3. Close the connection --> |
| <xsl:value-of select="sql:close($products)"/> |
| </xsl:template> |
| |
| <xsl:template match="row"> |
| <TR> |
| <xsl:apply-templates select="col"/> |
| </TR> |
| </xsl:template> |
| |
| <xsl:template match="col"> |
| <TD> |
| <!-- Here is the column data --> |
| <xsl:value-of select="text()"/> |
| </TD> |
| </xsl:template> |
| |
| </xsl:stylesheet> |
| </pre> |
| </body> |
| </html> |
